JWT Generator
Build and sign a JWT with HS256, HS384 or HS512 for testing.
JSON Schema Generator
Infer a draft-07 JSON Schema from a sample document in one step.
Quick Tool Overview
The JSON Schema Generator infers a draft-07 schema from one sample document: types for every field, a required list, nested definitions, and detected string formats such as email, date-time, uuid and uri.
- What it does
- Writes a JSON Schema from a sample document
- You give it
- One representative JSON payload
- You get back
- A draft-07 schema with types, required fields and formats
- Best for
- Documenting an API you did not design, and contract testing
About the JSON Schema Generator
Writing a JSON Schema by hand for an API you did not design is slow and error-prone. Paste one real response instead and the generator writes the schema: types for every field, a required list, nested object and array definitions, and detected string formats.
Format detection is what makes the output immediately useful. A value that looks like an email, a date, a date-time, a UUID, a URI, a hostname or an IP address is annotated with the matching format keyword. Arrays are handled by describing every element and merging the descriptions, so an array of slightly different objects produces one schema covering all of them, with the keys that are not always present left out of required.
Key features of the JSON Schema Generator
String formats detected
Values that look like an email, date, date-time, uuid, uri, hostname or IP address are annotated with the matching format keyword.
Arrays are merged, not sampled
Every element is described and the descriptions combined, so an array of slightly different objects produces one schema covering all of them.
Honest required lists
A key missing from any element of an array is left out of required automatically, rather than being asserted from the first record.
Strictness is a choice
Turn additionalProperties off to catch typos, or leave it open so an upstream API adding a field does not break your validation.
Draft-07 output
The draft with the widest library support, so the schema works in almost any validator without configuration.
How to use the JSON Schema Generator
-
1
Paste a sample document
One real response is enough; a representative one produces a better schema.
-
2
Set the options
Choose whether to emit a required list, detect string formats and forbid additional properties.
-
3
Review the schema
Check that optional fields really are optional and that inferred formats match your intent.
-
4
Copy or download
Take the schema to your clipboard or save it as a .json file.
Frequently asked questions
Draft-07, declared in the $schema keyword. It is the draft with the widest library support, and most validators accept it without configuration.
Every key present in the sample is required by default. If your sample is an array of objects, a key missing from any element is left out of required automatically.
It infers from one sample, so it cannot know that a field which happens to be an integer is sometimes a decimal, or that a null is really an optional string. Treat the output as a first draft and adjust.
It makes the schema reject any key it does not name. That is stricter and catches typos, but it also breaks the moment the API adds a field, so leave it off for schemas that validate third-party data.
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